718 Proceedings of the Royal Irish Academy. 



(h) A triangular stomacli, with three primary canals, one from 

 each corner of the stomach, and the usual accessory canals, 

 in different stages of development. (AUman's type.) 



[c) An elongated stomach, with a canal at each end and two canals 

 on each side ; also with accessory canals. (Boeck and 

 Haeckel's type.) 



The number of radial canals leaving the stomach (including those 

 which had not reached the ring canal) were counted in 217 specimens 

 taken in 1897 : the result is g-iven in the followins; table : — 



The number of 



Canals leavina; r, 



iv Ci 1, bpecimens. 



the Stomach. ^ 



The number of 



6. 3. 



6. 8. 



7. 18. 



8. 31. 



9. 43. 



10. 32. 



11. 31. 



12. 25. 



13. 11. 



14. 5. 



15. 6. 



16. 2. 



17. 1. 



18. 1. 



I do not think that there is any tendency on the part of the Medusa 

 to produce permanent blind canals, but that the aim of every canal on 

 leaving iihe stomach is to unite with the ring canal. In two specimens 

 I noticed a short canal running out fi'om the ring canal and directed 

 towards the stomach. As the radial canals are so irregular in number 

 and position it is not possible, until the earliest stages have been seen, 

 to express a definite opinion as to the normal type. Scarcely two 

 specimens have the canals in exactly the same position, and they 

 apparently develop in no definite order. 



Generative Organs. — According to Haeckel's definition of the genus 

 there ought to be six gonads ; Allman gives only three. The Yalencia 

 specimens used in the above table show that the gonads may be upon 

 all the canals, or only on a few ; the number of gonads ranges from 



